This invention relates to products for absorbing body fluids such as for example disposable diapers, sanitary napkins, panty liners and the like. In particular, the invention relates to such products having an exterior surface which is provided with an aesthetically pleasing pattern.
Absorbent products having patterns imposed upon their exterior surfaces are now on the market. For example, sanitary napkins or the thinner version thereof, the so called panty liners, comprise a cover of nonwoven material having a pattern of depressed areas impressed into the external surface thereof in such configurations as flowers, lines, spots and the like. Needless to say, for such patterns to be aesthetically effective, the pattern must be visible to the eye. Such patterns owe their visability to the fact that, as a result of the compression step forming them, the depressed areas tend to be smoother and therefore reflect a greater amount of light as compared with the undepressed areas. Further, the variations in the topography, i.e., the juxtaposition of depressed and undepressed areas, produces shadows which highlight the pattern of depressions. Accordingly, it can be seen that pattern visability for products relying solely on depressed areas for creating such a pattern is a function of the degree of compression and the depth of the depressions. Said in other words, the greater the compression and the greater the depth of the depressions, the greater the visual contrast between depressed and undepressed areas. Unfortunately, these factors of compression and depth cannot always be increased to the point where sufficient contrast is manifested. Increasing the degree of compression in some instances will adversely effect the product from a functional point of view, e.g., render the product less receptive to absorbing and retaining body fluids or rendering the body contacting surface of the product uncomfortably stiff or harsh for the wearer. Similarly, the depth of the depressions is constrained in practice in that exterior covers for some of the products considered herein are inherently thin and thicker covers, as are also sometimes used, do not always take a permanent set without resorting to extreme compression conditions or without substantially modifying the manufacturing process for such products.
In commonly assigned, copending, patent application U.S. Ser. No. 414,104 now U.S. Pat. No. 4,518,451 filed on Sept. 9, 1982, there is described a product and method for producing a depressed pattern on an absorbent product without creating the functional disadvantage of harsh longitudinal edges. The product described therein has a deep pattern of depressions on the body facing surface and a shallow pattern of depressions on its longitudinal edges, this configuration being obtained by use of an insert of absorbent material being compressed together with portions of the cover and uncompressed at other cover portions. While this solution is effective for the products described in the aforementioned patent application, it is not applicable to several other product configurations wherein the aforementioned shortcomings of relying wholly on compression to provide pattern contrast apply.
Accordingly, there is a need for improvement in providing a product with a high degree of visual pattern contrast.